{"id":"CVE-2021-4442","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: add sanity tests to TCP_QUEUE_SEQ\n\nQingyu Li reported a syzkaller bug where the repro\nchanges RCV SEQ _after_ restoring data in the receive queue.\n\nmprotect(0x4aa000, 12288, PROT_READ)    = 0\nmmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000\nmmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000\nmmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000\nsocket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3\nsetsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0\nconnect(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, \"::1\", &sin6_addr), sin6_scope_id=0}, 28) = 0\nsetsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [1], 4) = 0\nsendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base=\"0x0000000000000003\\0\\0\", iov_len=20}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 20\nsetsockopt(3, SOL_TCP, TCP_REPAIR, [0], 4) = 0\nsetsockopt(3, SOL_TCP, TCP_QUEUE_SEQ, [128], 4) = 0\nrecvfrom(3, NULL, 20, 0, NULL, NULL)    = -1 ECONNRESET (Connection reset by peer)\n\nsyslog shows:\n[  111.205099] TCP recvmsg seq # bug 2: copied 80, seq 0, rcvnxt 80, fl 0\n[  111.207894] WARNING: CPU: 1 PID: 356 at net/ipv4/tcp.c:2343 tcp_recvmsg_locked+0x90e/0x29a0\n\nThis should not be allowed. TCP_QUEUE_SEQ should only be used\nwhen queues are empty.\n\nThis patch fixes this case, and the tx path as well.","modified":"2026-03-13T05:14:59.899331Z","published":"2024-08-29T11:15:23.413Z","related":["SUSE-SU-2024:3566-1"],"references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/046f3c1c2ff450fb7ae53650e9a95e0074a61f3e"},{"type":"FIX","url":"https://git.kernel.org/stable/c/319f460237fc2965a80aa9a055044e1da7b3692a"},{"type":"FIX","url":"https://git.kernel.org/stable/c/3b72d5a703842f582502d97906f17d6ee122dac2"},{"type":"FIX","url":"https://git.kernel.org/stable/c/3bf899438c123c444f6b644a57784dfbb6b15ad6"},{"type":"FIX","url":"https://git.kernel.org/stable/c/8811f4a9836e31c14ecdf79d9f3cb7c5d463265d"}],"affected":[{"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-4442.json","unresolved_ranges":[{"events":[{"introduced":"3.5"},{"fixed":"4.19.181"}]},{"events":[{"introduced":"4.20"},{"fixed":"5.4.106"}]},{"events":[{"introduced":"5.5"},{"fixed":"5.10.24"}]},{"events":[{"introduced":"5.11"},{"fixed":"5.11.7"}]},{"events":[{"introduced":"0"},{"last_affected":"5.12-rc1"}]},{"events":[{"introduced":"0"},{"last_affected":"5.12-rc2"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}